Blank and process for making valve tappets



Oct. 6,1931. R. HERVIG 1,325,544

BLANK AND PROCESS FOR MAKING VALVE TAPPETS Filed Jan. 11, 1936 J71 a 1018 IIIII 7J5 jozard @r/ .valve tappets are either excessivel ing thecorresponding end Patented Oct. 6, 1931 UNITED STATES (PATENT OFFICERICHARD HERVIG,

DETROIT,

OI DETROIT, MICHIGAN, ASSIGNORAW RICH TOOL COMPANY, OF

MICHIGAN, A CORPORATION OF MAIN E Application filed January 11, 1926;Serial No. 80,426.

Metals that can long endure in the heads of expensive to machine, or0th, while or ver difficult y be readil machined, or can Y metals thatcan be purchased at reasonable cost, are not able to endure in the headsof valve tappets.

The principal object of this invention is to produce a tappet having itshead and shank of different metals suited respectively to those portionsand firmly united without stress or strain on the metals at, or adjacentto, the joint.

This object is attained by the structure and procedure illustrated inthe accompanying 2 drawings in which Fig. 1 is a sectional view througha finished tappet of the preferred form; Fig. 2 is a sectional viewthrough a head blank for producing the tappet shown in Fig. 1; and

Fig. 3 is a sectional view through the head and stem blanks and a bottomdie suitable for forging them to the form and condition indicated inFig. 1. v The preferred form of head blank 19, illustrated in Fig. 2,maybe roduced by casting, by forging a ball shape blank with suitabledies, by subjecting a bar to a Bradley hammer, or in any other way thatmay be selected. This blank roughly approximates the head of thefinished tappet and requires no great amount of forgin to give thecompletely finished form and secure it to the surrounded by an annularflange 12, whereby ared for receiva tubular shank 14in the relationillustratedin Fig.-3. 1

With the parts assembled as indicated in this figure, the shank issupported at proper height by a knock-out plug 15 and the head blank 10is acted upon by a hammer or flat die to force it to fill the cavity 16in the bottom die 17.

The upper surface of the blank 10 1s provided with a disk-like recess 18to cause the initial forging operation to affect the outer portion ofthe blank chiefly and causethe anan annular groove 13 is pre nularflange 12 to flow well down into the cavity 16 and around the end of theshank 14. The result of this operation is illustrated in Fig. 1, wherethe end portion of the shank has been forged to form a flaring flange 19above a reduction, or constriction 20, and the boss 11 and flange12 aremade to grip the flaring flange 19 and firmly secure it in What wasformerly the groove 13.

Both the head and shank blanks should be heated during the forgingoperation so that in cooling they can shrink together and leave themetal of the two blanks in intermediate contact throughout the matingsurfaces without stress or strain in either part. If, for example, theshankis, forged cold, there will be some movement along the surfaces ofcon- .tact as the head metal cools and shrinkage strains will remain inthe head metal after coolmg which, to a greater or less. extent,vitiates the joint.

The blanks may be heated in any suitable manner, but preferably they arebrought to a forging temperature after being assembled in the die by theapplication of suitable electric current. One electrode may be applieddescends.

\ a The head metal may be of any material of suflicient hardness, orcapable of having sufficient hardness imparted to it. Hi h speed toolsteel or steel containing tung ten as a hardening material or wearresisting element is very sultable; cast material that is forgible whenin cast form ma be used; an alloy composed of sixty (60%; percentcobalt, thirty percent chromium and the remainder chiefly iron, makes avery satisfactory head. Another alloy containing sixty per cent nickel,thirty (30%) percent chromium, seven (7%) percent aluminum, and theprincipal remainder iron, is also satisfactory.

The shank blanks may be made of a great variety of readily machinedmaterial, ordinarily .10% to .20% carbon steel, with or without threeand one-half percent (3%%) nickel, is very satisfactory. This materialcan be readily. carburized after finishing and to the bottom die and theother to the head before forging. ;50% used and hardened in oil ifcarburizing is not resorted to to obtain suitable hardness.

I claim as my invention:

-\1. The process which includes forming a cad blank with an annularrecess on the bottom, inserting a'tubular shank in the recess andforging a flange on the shank, and gripping the flange between portionsof the head blank metal, the initial forging operation bein directedchiefly to the marginal portion 0 the head blank to force the metaldownwardly and inwardly against the shank.

2. The process which includes forming a headblank with a boss on thebottom surrounded by a flange, and a marginal rojection on the top,resting the head blan i on a tubular shank and simultaneously forging aflange on the shank arid gripping the flange between the boss and thesurrounding flange on. the head blank, the'marginal projection servingto provide extra metal in that area and to facilitate the movement ofthe metal in the bottom flange for the specified purpose.

3. A blank of the class described, having on the bottom a bosssurrounded by aflange, and on top a m'ar inal flange.

In testimony w ereof I aflix my signature.

\ RICHARD HERVIGr;

carbon steel may be I

